"The Justice Department is investigating whether former Interior Secretary Gale A. Norton illegally used her position to benefit Royal Dutch Shell PLC, the company that later hired her, according to officials in federal law enforcement and the Interior Department.

The criminal investigation centers on the Interior Department's 2006 decision to award three lucrative oil shale leases on federal land in Colorado to a Shell subsidiary. Over the years it would take to extract the oil, according to calculations from Shell and a Rand Corp. expert, the deal could net the company hundreds of billions of dollars.